[LT4Greg]

People can use what they want in their Camaros but this person will continue to use 5w30 in his 2017 ZL1!

[ZX-10R]

Again if you actually look up the viscosity at 40 and 100 C they aren't much different - so that isn't why the pumps are failing.

Aggressive throttle on cold oil *may* be a contributor. I always make sure the oil is up to temp before getting hard on the gas

https://www.mobil.com/en-gu/passenge...x-mobil-1-0w40
https://www.mobil.com/en-us/passenge...x-mobil-1-5w30

[SJFGTO]

Originally Posted by ZX-10R

Again if you actually look up the viscosity at 40 and 100 C they aren't much different - so that isn't why the pumps are failing.

Aggressive throttle on cold oil *may* be a contributor. I always make sure the oil is up to temp before getting hard on the gas

https://www.mobil.com/en-gu/passenge...x-mobil-1-0w40
https://www.mobil.com/en-us/passenge...x-mobil-1-5w30

^^^Agreed^^^

[ZX-10R]

15W-50 (racing oil) is considerably higher viscosity of course. It would be interesting to see if there is any connection between owners running 15W-50 (track events) and pump failures, and how oil pressure changes with that grade.

https://www.mobil.com/en/lubricants/...obil-1-15w-50/

[Gunkk]

Originally Posted by zx9rmal

I thought I would post this experience. I'm a very knowledgeable car guy. I no longer change my own oil. At 73, I'm not as inclined anymore.

So, I've been reluctantly using the dealer, who makes sure their hi perf guy does it. I've had no problems so far and I don't leave the dealer without checking the oil level.

I used a well known, well respected performance shop a while back to dyno my car, so I thought I'd let them do the oil change. I asked what oil they use. I was told AC Delco. I asked why. I was told it was "because Mobil 1 isn't very good". Huh? Interesting. Then, I asked exactly what AC Delco oil they use. He said 5W-30. I told him the owner's manual calls for 0-40.

Here's what he said:

"We use 5w30 being it is a much better choice over the recommended 0w40 that the dealership uses, especially for our hot environment."

Is it me, or does this not make sense?

Your experience is serving you well. The the shop is clueless if they are trying to sell you on "lower viscosity oil is better in a hot environment."

They probably a) would have to special order it, and b) just don't want to pay double for the good stuff... even though they'd just upcharge you for it.

[Gunkk]

Originally Posted by Vigilante375

5w will do better in warmer environments (above ~30 degree's) compared to 0w. 0w will be better in colder environments (below ~30 degree's) than 5w.

This is not always true, and I suspect is the assumption made by the OP's shop.

Partularly in the case of Mobil1 dexos oils for our Camaros, the 5W-30 actually has both a lower cold and lower hot viscosity than the 0W-40 Forumla ESP, as seen in the above links.

So the 5w30 is the better cold oil.

[Vigilante375]

Originally Posted by Gunkk

This is not always true, and I suspect is the assumption made by the OP's shop.

Partularly in the case of Mobil1 dexos oils for our Camaros, the 5W-30 actually has both a lower cold and lower hot viscosity than the 0W-40 Forumla ESP, as seen in the above links.

So the 5w30 is the better cold oil.

This article is to the point but explains why 5w is better in hotter environments

https://www.mrtonneau.com/0w-40-vs-5w-30/

[ZX-10R]

Where on earth did you dig up that garbage link? Try something peer reviewed by ASME if you want actual science. The 100 C viscosity for M1 is posted in the previous links, that's number you should be concerned with in terms of high temp protection. I don't think many care about cold start-up, which is an overblown issue anyway, as long as you're easy on the throttle the first 5-10 minutes as the oil reaches temp

As far as viscosity, I'm going to trust the GM engineers and use 0W-40 - only change is I prefer Castrol Edge because I don't want to pay for the Dexos label mark-up. Edge meets even more stringent Euro standards anyway.

[hawk02]

The OP didn’t mention if the 5W30 oil used by the performance shop is Dexo 2 certified. That’s just a critical as the weight.

[Stephen12ZL1]

Originally Posted by ZX-10R

15W-50 (racing oil) is considerably higher viscosity of course. It would be interesting to see if there is any connection between owners running 15W-50 (track events) and pump failures, and how oil pressure changes with that grade.

https://www.mobil.com/en/lubricants/...obil-1-15w-50/

good thought but my '17 A10 failed without using 15w50 on track...agreed thicker oil would cause the pump to work harder

[ZX-10R]

But you did run 15W-50 for a period of time?

You could have had stress cracks before the pump actually failed - just a thought

15W-50 is pretty extreme

Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 =18

Kinematic Viscosity @ 40 C, mm2/s, ASTM D445 = 125

Compared to 0W-40

Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 =12.9

Kinematic Viscosity @ 40 C, mm2/s, ASTM D445 =71

Quite a few modern engines are running 0W-20 now (!)

[Stephen12ZL1]

never ran 15w50 ever...on track or street. I ran 0w40, 5w40, and 5w30. Mostly Valvoline 5w40 MST. That link from "Mr. Tonneau" is laughable.

[Vigilante375]

Originally Posted by ZX-10R

Where on earth did you dig up that garbage link? Try something peer reviewed by ASME if you want actual science. The 100 C viscosity for M1 is posted in the previous links, that's number you should be concerned with in terms of high temp protection. I don't think many care about cold start-up, which is an overblown issue anyway, as long as you're easy on the throttle the first 5-10 minutes as the oil reaches temp

As far as viscosity, I'm going to trust the GM engineers and use 0W-40 - only change is I prefer Castrol Edge because I don't want to pay for the Dexos label mark-up. Edge meets even more stringent Euro standards anyway.

Because I didn't grab the first thing off of Google.......

How about this? https://bobistheoilguy.com/motor-oil-101/ Is that better?

[Vigilante375]

Originally Posted by ZX-10R

15W-50 (racing oil) is considerably higher viscosity of course. It would be interesting to see if there is any connection between owners running 15W-50 (track events) and pump failures, and how oil pressure changes with that grade.

https://www.mobil.com/en/lubricants/...obil-1-15w-50/

But the oil pump failures started with the 2017 ZL1. Before the 1lLE and it having to use the 15w50 oil. It's possible but I don't think the cause.